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Old 12-18-2007, 09:24 AM
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427v8 427v8 is offline
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Static toe and dynamic ( roll or bump steer) cause completely different issues.
Static Toe in, at ride height, makes the car drive in a nice straight line, too much will wear the tires. Toe out will make the car like to turn, great for roadracing, not so good for street driving.

Dynamic toe changes, come in two flavors which are manifestation of the same thing.
In most suspension systems bump steer and roll steer are caused by the same suspension adjustments and cannot be adjusted seperately ( unfortuneately)

Bump steer you are driving aloog and one wheel hits a bump ( or a hole), the wheel should sty pointing where it was before, it shouldn't turn as it goes over the bump. Any turning, toe in or out, will make the car feel unstable.

Roll steer is what happens when you go around a corner, the car rolls and puts more weight on the outside wheels.
More weight causes compression of the suspension just like going over a bump.
Again, if the wheel turns, the driver will have to compensate.

But it's more complicated than that...
If the car toes in on roll, the car will turn sharper, causing more roll, causing more turn...the driver will compensate by straightening the wheel, which causes less roll, less toe in, less steering...So the driver will turn sharper, back to square 1 !
This is oversteer, and is unnerving to the driver.

If the car toes out on roll, the car won't turn as much as the driver expects, so they will turn a little more. end of story.
This is understeer, and a little makes the car feel stable and predictable, a lot makes the car feel like a Ford, sluggish and unresponsive.

BTW roll steer is what makes a car want to turn into the ditch on a crowned road, it because the car is leaning just like going around a corner.
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